Fig. 8

Fiber type–specific distribution of selected proteins revealed by immunofluorescence analysis. Fiber types are labeled as 1 (type 1), 2A (type 2A), or 2X (type 2X). Hybrid 2A–2X fibers are labeled by asterisks. A–D Type 1–specific proteins. Each panel shows on the left a section stained for PGM5/aciculin (A), PDLIM1 (B), MCU (C), or IDH2 (D) and on the right a serial section stained with MYH-specific antibodies to reveal the three fiber types. No pure type 2X fibers is present in A and B. E–F Type 2–specific proteins. Each panel shows on the left a section stained for ACTN3 (E) or XIRP2 (F), on the center a serial section stained for MYH-specific antibodies to reveal the three fiber types, and on the right a section stained with anti-MYH antibody BF-35, which reacts with MYH7 and MYH2 but not with MYH1, thus stains all fiber types, except pure type 2X fibers. Note that whereas ACTN3 is especially abundant in type 2X fibers, as well as in hybrid 2A–2X fibers, XIRP2 is present at higher levels in both 2A and 2X fibers. WGA counterstain was applied to all sections, except those processed with the three anti-MYHs antibodies